1. Field of the Invention
The present invention relates to a press-connecting connector in which an electric wire of the wiring, installed in a vehicle, can be properly press-fitted into a press-connecting terminal without cutting a conductor thereof. Further, the present invention relates to a wire press-fitting apparatus for press-fitting an electric wire into a press-connecting terminal.
The present application is based on Japanese Patent Application No. Hei. 11-315393, which is incorporated herein by reference.
2. Description of the Related Art
In vehicles having various electronic equipments mounted thereon, press-connecting connectors have been extensively used for connecting the electronic equipments together and for connecting wire harnesses together. As shown in FIG. 6, a conventional press-connecting connector 10 comprises a connector housing 11, having an insertion opening formed in its front side for receiving a mating connector, and press-connecting terminals 1. The press-connecting terminal 1 is formed by cutting and bending an electrically-conductive metal sheet.
The press-connecting terminal 1 includes a connection portion for being resiliently electrically connected to a connection terminal (not shown) in the mating connector inserted in a direction of arrow A, a press-connecting portion 4 for press-fitting an electric wire 7 thereinto in a direction of arrow B, and a clamping portion 4 having a pair of retaining piece portions 8a and 8b for press-holding the electric wire 7 through a sheath 7a of this wire. The press-connecting portion 4 includes three pairs of press-connecting blades 9 each pair of which cut the sheath 7a to press-contact and hold a conductor 7b of the electric wire in electrically-connected relation thereto.
As shown in FIG. 7, each pair of press-connecting blades 9 are formed respectively by cutting opposed side plates 2a respectively at regions 2b adjacent to a bottom wall 2c and then by bending these portions inwardly. The pair of press-connecting blades 9 have respective bladed, tapering guide surfaces 9a each slanting inwardly downwardly from an upper end surface 9d, and each bladed, tapering guide surface 9a has an edge 9b formed along its slanting surface by cutting.
The pair of press-connecting blades 9 have a pair of opposed inner surfaces 9c and 9c which extend downwardly from their respective bladed, tapering guide surfaces 9a, with a gap G formed therebetween, the gap G being smaller than the diameter d of the conductor 7b (see FIG. 6).
When the electric wire is press-fitted between the pair of press-connecting blades 9, their edges 9b cut the sheath 7a of the electric wire, while gradually compressing and deforming the outer diameter of the electric wire by their bladed, tapering guide surfaces 9a. When the electric wire 7 is further press-fitted, the edges 9b cut the sheath 7a. 
The gap G is thus smaller than the diameter d of the conductor 7b (G less than d), and in this case, the conductor 7b, comprising a stranded wire comprised of thin wires twisted together, is deformed into a vertically-spread shape by the downwardly-extending inner surfaces 9c, and is exposed through cut portions of the sheath 7a, and therefore contacts the downwardly-extending inner surfaces 9c. 
As shown in FIG. 8, the electric wire 7 is press-fitted relative to the press-connecting blades 9 by the use of a wire press-fitting apparatus 20, and this wire press-fitting apparatus 20 broadly has the following construction. Namely, the wire press-fitting apparatus 20 comprises a vertically-movable hollow body portion 21, a press-fitting rod portion 22 which can project downwardly along an axis CL of the hollow body portion 21, and a pair of press-connecting blade pressing portions 23 resiliently suspended in an internal space 21a of the hollow body portion 21 through spring members 24. Each of the press-connecting blade pressing portions 23 has a stepped lower end surface 23a for fitting on step portions of the upper end surfaces 9d of the corresponding press-connecting blades 9.
In the process of moving the hollow body portion 21 downward to a lower limit in the wire press-fitting apparatus 20, first, the lower end surfaces 23a of the press-connecting blade pressing portions 23 are brought into contact with the upper end surfaces 9d, and resiliently presses these end surfaces 9d, thereby firmly positioning the press-connecting blades 9. Then, a lower end 22a of the press-fitting rod 22 forces the electric wire 7 into the gap between each pair of the opposed, downwardly-extending inner surfaces 9c and 9c via the bladed, tapering guide surfaces 9a. 
When the electric wire 7 is gradually forced into the gap between each pair of downwardly-extending inner surfaces 9c and 9c via the bladed, tapering guide surfaces 9a, each pair of press-connecting blades 9 tend to be displaced away from each other respectively toward side walls 11b of the connector housing 11. However, the lower end surfaces 23a of the press-connecting blade pressing portions 23 are engaged with the upper end surfaces 9d of the press-connecting blades 9 at their step portions, and therefore the press-connecting blades 9 are prevented from displacement, so that the gap G between each pair of press-connecting blades 9 is kept constant.
In the above conventional press-connecting connector 10, however, there are occasions when variations in thickness of the sheath 7a and diameter d of the conductor 7b develop. In this case, when the electric wire 7 is forced into the gap G in the press-connecting terminal 1, the conductor, having a diameter larger than the predetermined diameter d, is excessively cut by the edges 9b. As a result, the degree of press-contact of the conductor 7b with the opposed, downwardly-extending inner surfaces 9c decreases, and an electrical resistance at the area of contact between the conductor and each downwardly-extending inner surface 9c increases to generate heat, so that those members around the press-connecting portion 4 are subjected to deterioration, improper contact and so on, and this has invited a problem from the viewpoint of safety of the vehicle.
It is an object of the present invention to solve the above problems of the conventional construction, and more specifically to provide a press-connecting connector in which a conductor of an electric wire can be properly press-fitted into a press-connecting portion without being excessively cut, and also to provide a wire press-fitting apparatus for use with this press-connecting connector.
To achieve the above object, according to the first aspect of the present invention, there is provided a press-connecting connector which includes:
a connector housing including a terminal receiving chamber; and
a press-connecting terminal insertable into the terminal receiving chamber, the press-connecting terminal including:
a base,
a connection portion, to which a terminal of a mating connector is electrically connectable, disposed on the base, and
a press-connecting portion, to which a conductor of an electric wire is electrically connectable, disposed on the base, the press-connecting portion including a pair of press-connecting blades which have:
a pair of bladed, tapering guide surfaces which slant inwardly downwardly, and
a pair of opposed inner surfaces, between which a gap smaller than a diameter of the conductor of the electric wire is formed, and which downwardly extend respectively from the pair of tapering guide surfaces;
wherein when the electric wire is press-fitted into the gap, the conductor of the electric wire is electrically connected to and held by the pair of press-connecting blades,
wherein a receiving width between opposed side walls of the terminal receiving chamber, receiving the press-connecting portion, is larger than a width of the press-connecting portion, and
wherein the pair of press-connecting blades are tilted respectively toward the opposed side walls when the electric wire is press-fitted into the gap, so that the opposed inner surfaces of the press-connecting blades are outwardly expanded into a generally V-shape.
In the press-connecting connector of the above construction, the degree of displacement of the press-connecting blades away from each other varies in accordance with the outer diameter of the electric wire, and edges, formed respectively along the bladed, tapering guide surfaces, can properly cut a sheath of the electric wire without cutting the conductor.
Further, to achieve the above object, according to the second aspect of the present invention, there is provided a wire press-fitting apparatus for press-fitting an electric wire into a press-fitting portion of a press-fitting terminal, including:
a hollow body portion which is vertically movable;
a press-fitting rod portion which can project downwardly along an axis of the hollow body portion; and
a pair of pressing portions, which are operative to press a pair of press-connecting blades of a press-fitting portion of a press-fitting terminal, and which are resiliently suspended in an internal space of the hollow body portion through spring members;
wherein each of the pair of pressing portions has a flat lower end surface for pressing an upper end surface of the corresponding press-connecting blade, and
wherein, in accordance with the press-fitting of the electric wire, the pair of press-connecting blades slightly push the lower end surfaces of the pressing portions back upwardly through the upper end surfaces, so that the pair of press-connecting blades are tilted respectively toward opposed side walls of a connector housing with a result that opposed inner surfaces of the press-connecting blades are outwardly expanded into a generally V-shape.
In the wire press-fitting apparatus of the above construction, the edges, formed respectively along the bladed, tapering guide surfaces, can properly cut the sheath of the electric wire without excessively cutting the conductor.